Wart-biter

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Wart-biter
Decticus verrucivorus (42083043185).jpg
Adult female of the green morph
Decticus verrucivorus male (3788390082).jpg
Male
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Orthoptera
Suborder: Ensifera
Family: Tettigoniidae
Subfamily: Tettigoniinae
Tribe: Decticini
Genus: Decticus
Species:
D. verrucivorus
Binomial name
Decticus verrucivorus
Close-Up of a Decticus verrucivorus
Gnome-mime-sound-openclipart.svg
Sound of Decticus verrucivorus
Field recording in the Netherlands 30s
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The wart-biter (Decticus verrucivorus) [1] is a bush-cricket in the family Tettigoniidae. Its common and scientific names derive from the eighteenth-century Swedish practice of allowing the crickets to nibble at warts to remove them. [2]

Contents

Description

Adult wart-biters are 31–37 millimetres (1.2–1.5 in), with females being significantly larger than males. They are typically dark green in colour, and shiny, [3] always with at least some dark brown mottling or blotches on the pronotum and wings; a largely dark brown morphotype also occurs, though still mottled with some green. The female has a 20 mm long and slightly upcurved ovipositor. [4] [5] Their colour acts as effective camouflage in grassy surroundings. [3]

The wart-biter has a song consisting of a rapidly repeated series of short bursts of clicks starting slowly and speeding up, sometimes lasting for several minutes; it only sings in sunny weather. [5]

Wart-biters normally move around by walking; they rarely fly, except when frightened. Most can only fly 3 to 4 metres (10 to 13 ft) at a time.

Subspecies

The Orthoptera Species File [6] lists:

Habitat

The species is found in calcareous grassland and heathland habitats. [4]

Wart-biters need a mosaic of vegetation, including bare ground/short turf, grass tussocks, and a sward rich in flowering herbs. They prefer areas that are not heavily grazed. The species is thermophilous, and tends to occur on sites with a southerly aspect. [7]

Diet

Wart-biters are omnivores. [3] Plants eaten include knapweed, nettles, bedstraws; the species also eats insects, including other grasshoppers.

Life cycle

The wart-biter lays its eggs in the soil; these eggs normally hatch after two winters. It then passes through seven instar stages between April and June. The adult stage is reached in the beginning of July. Wart-biter populations peak in late July and early August. [4] Newly hatched Decticus are encased in a sheath to facilitate their trip to the soil surface, the sheath holding the legs and antennae safely against the body while burrowing upwards. A neck which can in turn be inflated and deflated, enlarges the top of its tunnel, easing its passage upwards. [8]

Status and distribution

This species occurs throughout continental Europe, except the extreme south, ranging from southern Scandinavia to Portugal, Spain, Italy, and Greece. It is also found in temperate Asia, as far east as China. Geographic features such as mountains have fragmented the species, leading to a wide range of forms and numerous subspecies. [9]

In Britain, the wart-biter is confined to five sites, two in East Sussex, and one each in Wiltshire, Essex, Dorset and Kent. [4]

Conservation

The population of wart-biters has declined in many areas of northern Europe. In Britain, it is threatened with extinction. [10] The species is the subject of a United Kingdom Biodiversity Action Plan. [11]

References

  1. ↑ "Wart-biter bush-cricket | Buglife". www.buglife.org.uk.
  2. ↑ "Rare wart-biter cricket's powers put to the test". BBC News. Retrieved 9 August 2020.
  3. 1 2 3 Westwood & Moss 2017, p. 307.
  4. 1 2 3 4 Judith A. Marshall & E. C. M. Hayes (1988). Grasshopper and allied insects of Great Britain and Ireland. Harley Books. ISBN   0-946589-36-4.
  5. 1 2 Chinery, Michael (1986). Collins Guide to the Insects of Britain and Western Europe. London: HarperCollins. p. 50. ISBN   0-00-219137-7.
  6. ↑ Orthoptera Species File: species Decticus verrucivorus (Linnaeus, 1758) (Version 5.0/5.0 retrieved 8 February 2021)
  7. ↑ Dag Øystein Hjermann & Rolf Anker Ims (1996). "Landscape ecology of the wart-biter Decticus verrucivorus in a patchy landscape". Journal of Animal Ecology . 65 (6). British Ecological Society: 768–780. Bibcode:1996JAnEc..65..768H. doi:10.2307/5675. JSTOR   5675.
  8. ↑ Jean-Henri Fabre - "Book of Insects"
  9. ↑ M. J. Samways & K. Harz (1982). "Biogeography of intraspecific morphological variation in the bush crickets Decticus verrucivorus (L.) and D. albifrons (F.) (Orthoptera: Tettigoniidae)". Journal of Biogeography . 9 (3). Blackwell Publishing: 243–254. Bibcode:1982JBiog...9..243S. doi:10.2307/2844667. JSTOR   2844667.
  10. ↑ Andrew A. Cunningham; J. Mick Frank; Pat Croft; Dave Clarke & Paul Pearce-Kelly (1997). "Mortality of captive British wartbiter crickets: implications for reintroduction programs" (PDF). Journal of Wildlife Diseases . 33 (3): 673–676. doi: 10.7589/0090-3558-33.3.673 . PMID   9249724.
  11. ↑ "United Kingdom Biodiversity Action Plan for the Wart-biter". Archived from the original on 2006-06-21. Retrieved 2006-07-22.

Bibliography

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